Theoretical Investigation of the Bonding Properties of Bis（glycinato） d8metal（II） Dihydrate Complexes Using Density Functional Theory

Density functional theory （DFT） approach has been applied for the analysis of the bond between the [（H20）2] and the [M（gly）2] fragments in a series of trans and cis [M（gly）2[（H20）2] complexes. For comparative purpose, both relativistic and non-relativistic calculations have been performed. The nature of the interaction between the [（H20）2] and [M（gly）2] fragments was investigated using energy decomposition analysis, Hirshfeld atomic charge variation, molecular orbital considerations and bond order decomposition analysis, respectively. Results reveal that the [（H20）：]-[M（gly）2] interaction lies from the hydrogen bridge interaction between these fragments. The strength of the bonding increases in the order Ni2＋ 〉 Pd2＋ 〉 Pt2＋ while the relativistic correction tends to strengthen the [（H2O）2---[M（gly）2] bond in the order Ni 〈 Pd 〈 Pt.